Authored by Brig. Gen. Houston Cantwell, USAF (Ret.), Senior Resident Fellow for Airpower Studies Russia and China have spent the past three decades developing and fielding advanced weapons capable of striking the U.S. homeland—this includes nuclear and non-nuclear missiles. Military and civilian targets are more vulnerable to aerial attack than ever before. This is a major driver behind Golden Dome. A Russian aircraft launching a hypersonic missile could strike New York or Washington D.C. in less than 60 minutes. Advanced cruise missiles—which are available in high numbers and at a low cost—can transit thousands of miles, evade existing radars, fly unpredictable flight paths, and deliver disastrous effects. The current devastation of major Ukrainian cities serves as a warning of what the United States could face in a future conflict. Nowhere is the country’s exposure to attack more acute than from its Arctic approaches—the most direct corridor through which both Russia and China could strike the United States.  America has dealt with similar threats before. The Cold War saw the United States install and operate extensive arrays of early warning systems to ensure advanced detection of Soviet bomber aircraft across the Arctic region. However, those systems have aged out. U.S. Arctic domain awareness capabilities and capacity are woefully insufficient to meet today’s threats. A modern, effective enterprise must detect, track, and analyze military movements and other activities in real-time by using a variety of air, surface, and space sensors that collect and share information from multiple domains. It is time for the nation to rebuild its northern tier defenses.